CHARACTERISTIC OF SEQUENCE STRATIGRAPHIC TRELLIS OF B FORMATION OF PALEOGENE IN DEEPWATER AREA IN THE A BASIN OF SOUTH CHINA SEA

Guided by classical sequence stratigraphy theory of Vail,and aimed at the difficulties of poor seismic data quality,no well data,complexity of faults,stratum fragmentation and stratigraphic sequence interfaces unsigned that formed by high temperature and high pressure of B Formation,finely carved up the stratum of B Formation of Paleogene in deepwater area.In this process,the well data of shallow water area and the seismic date of deepwater area were used,and five sequence interfaces of SB0,SB1,SB2,SB3 and SB4 were identified.Then the stratum of B Formation of Paleogene were divided into four third-class sequences of SⅠ,SⅡ,SⅢ and SⅣ,and the three-dimensional isochronous stratigraphic sequence trellis of B Formation in the study area were founded.The study results show that reasons of the space-time distributing characteristic of each sequence were differently depositing,partly ascending and denudation effect and rift faulting.Slope fan and basin floor fan developed in LST and fan deltas developed in HST were stratigraphic traps developed areas and favorable areas of prospecting.